It is desirable to have products that contain a volatile solvent because the volatile solvent provides for a better "feel" of the product when applied to the skin. The problem encountered with these types of formulations is that they readily lose the volatile solvent contained within their composition due to evaporation from the product.
The loss of a volatile solvent from a product can adversely affect the physical properties of the product as well as reduce the amount of volatile delivery. Even when not stored above room temperature, it has been noted that there is loss of the volatile solvent over time.
A standard cosmetic compact, which is used to hold non-volatile solvent containing products, is composed of a base and a cover. The base and the cover are attached to each other by a hinge which allows the cover to swing away from the base, thus exposing the product. To keep the cover in contact with the base when the cover is closed, a latch is typically provided. This latch is effective in keeping the cover of the compact closed, but does not provide an airtight seal. This is because the cover and the base of the compact have inherent manufacturing tolerances which do not permit an airtight seal to be made when the cover is in the closed position, thus making a standard compact ineffective for use with a volatile solvent-containing product.
Currently, there are many compacts that provide a seal which prevents the loss of a volatile solvent from a product. These compacts provide for the sealing of the product from the external environment through the use of a screw caps, liners and gaskets, additional covers, and combinations of these elements.
Typical screw cap sealing compacts are such as those disclosed in JP 8256829. With this style of sealing compact, a separate compartment is provided for the product. This compartment has an outer wall which contains a threaded finish. Over this outer wall is placed a cap with a matching internal thread. The cap is then screwed onto the compartment just as a cap is screwed onto a bottle. The inside of the cap can be provided with a deformable liner which will assist in making a seal along the top edge of the compartment wall when the cap is closed. The drawback to this type of sealing compact is that, in order to gain access to the product, the consumer must first open the compact cover and then unscrew the cap. These multiple steps can sometimes be annoying and confusing to a consumer, thus detracting from the consumer acceptance of such a package.
Sealing compacts, such as those of JP 9037838, utilize an elastic packing material to effectuate a seal. This packing material is in the form of a solid o-ring, placed within a groove in the base, in which the o-ring deforms as it is contacted by a protrusion from the cover. When the solid o-ring deforms, it makes a seal around the cover protrusion. This compact style is, however, difficult to seal because it requires the accurate manufacture of the protrusion that contacts the o-ring, the groove within the base, and the o-ring itself. Furthermore, the solid o-ring requires the consumer to exert a greater amount of force when closing the cover. This is because the consumer has to deform a solid structure before the cover can be held in place via the clamping mechanism.
Dual covers have also been used to provide a seal within a compact (see JP 8154730, JP 8140728, and JP 9037838). This configuration requires the consumer to basically open two compartments, first the cover, and then the covering over the product, before application of the cosmetic. This style is labor intensive for the consumer, because she is required to open the cover of the compact and then open the covering of the product to gain access to it. After that, the consumer then has to close the covering of the product so that she can view herself in the mirror located within the first cover while applying the cosmetic.
The use of a liner within the cover, as disclosed in JP 8191712, JP 8168411, JP 8150016, JP 8140729, JP 8140728, JP 8126524, JP 8038243, JP 8238123, JP 8080961, JP 8080960, JP 8131248, and JP 8191714, has also been used to obtain a seal within the compact. The liner within these compacts engages a raised flange surrounding the product compartment so as to ensure a seal. This engagement causes the force required to close the compact to increase, and in turn, requires the use of a more secure locking mechanism which can withstand this added force without releasing its hold.
Friction fit seals have also been used to seal a compact. U.S. Pat. No. 4,586,519, discloses the use of opposing annular rims which engage each other circumferentially when the compact cover is closed. In order to provide a reliable seal for this type of compact, the annular rims must be precisely molded so that they will contact each other along all points. The molding accuracy required for this construction increases the cost of the compact, and if not controlled properly will not result in an effective seal.
This invention provides for an airtight container which prevents the loss of a volatile solvent from the product.
This invention also provides for an airtight container which does not require additional steps or a significant degree of force to open and close the cover.
Also, this invention provides for an airtight container which has few parts and is simple to assemble.
This invention also provides for an airtight container which is a relatively simple device that avoids interference with the package aesthetics.